Open source wireless router firmware may become tougher to install in the United States, if not illegal. That's if device manufacturers interpret new Federal Communications Commission (FCC) rules involving radio frequencies to mean that user-modified software should be banned.

The rules require manufacturers of wireless routers to "implement security features in any digitally modulated devices capable of operating in any of the U-NII bands, so that third parties are not able to reprogram the device to operate outside the parameters for which the device was certified."

In non-geek terms, that means users shouldn't be able to change their routers's radio frequencies, transmit power settings or other characteristics that violate the certified operating rules of the device. Those are all things that Linux-based open source router firmware, including dd-wrt and OpenWrt, can do.

This rule isn't simply the result of the FCC trying to make Linux fans' lives harder. There are good reasons for restricting users' ability to change the frequencies or power settings of wireless routers. For example, routers operating on frequencies for which they are not certified could interfere with other forms of wireless communication, intentionally or not. Similarly, users with malicious intent could use modified firmware to clog the airwaves with data in a way that prevents people around them from getting online.

On the other hand, open source fans will object that there are good reasons for using open source firmware. The most important is that the software that ships with most consumer-grade wireless routers only lets users take advantage of a fraction of the capabilities that the hardware can support. For example, if you want to use your router to repeat and extend the range of an existing wireless network, rather than create a new network, you could spend lots of money on a device marketed specifically to do that. Or you could download dd-wrt for free and repurpose an old router as a wireless repeater.

Fortunately, the FCC rules don't explicitly prevent users from modifying router firmware or require device manufacturers to make such modifications impossible. The potential danger for open source firmware fans is that device manufacturers will decide that banning firmware modifications is the easiest way to enforce the FCC's new policy.

There are other solutions to this problem that could be mutually beneficial to both manufacturers and users. One would be to start shipping routers with more advanced configuration features to allow users to do the things that are currently possible in many cases only by using open source firmware. Companies that do so would enjoy an edge in the market not only among the relatively small number of power users who want to configure their routers in unusual ways, but also resellers and service providers who need easily modifiable devices for their business.

Even better would be for device manufacturers to open source their firmware code—which in many cases is already based on Linux—completely, excepting modules or other bits of code that could be used to violate the FCC certifications. That way, users would have no need to install third-party firmware, since they could work with the code base from manufacturers themselves.

At any rate, it's unlikely that manufacturers could completely prevent users from modifying firmware in the first place. Chances are good that open source enthusiasts would figure out a work-around—by replacing the chips inside devices that contain the code designed to prevent modifications, for example.

Users could also simply purchase devices made for markets beyond the FCC's jurisdiction, which would presumably not place restrictions on firmware modification. The global nature of the hardware market makes things such as DVD region encoding futile. It would do the same for bans in the United States on firmware changes.